Springless switch constructions for use in the protective circuit of burglar alarm systems

ABSTRACT

A conductive permanent magnet structure fixed on the frame of a protected opening, attracts into contact with itself, a conductive loosely slidable armature having limited movement on the closure member; such magnet and slide constituting a switch protecting the opening. In closed condition of the switch, these switch parts are contiguous portions of the current path in the protective circuit. In installations where slide movement during the attraction is vertical, gravity returns the slide to a rest position, to be ready for a reestablishment of the protective circuit. When such direction is horizontal, the slide is automatically cammed to be in proper position if necessary, for the protective circuit to be put into operative condition. These switches avoid the need of cords across a parting of the frame and its closure. Stocking a few parts, affords the fabrication of switches of different constructions, either in the shop or on the job, to meet installation requirements and conditions.

United States Patent Lea [ Jan. 18, 1972' [54], SPRINGLESS SWITCHCONSTRUCTIONS FOR USE IN THE PROTECTIVE CIRCUIT OF BURGLAR ALARM SYSTEMS[72] Inventor: Lawrence N. Lea, 3601 .lo h nson Avenue,

Bronx, N.Y. 10463 [22] Filed: Dec. 7, 1970 121] App]. No.: 95,817

[52] U.S. Cl ..335/205, ZOO/61.62, 340/274, 335/285 I51] Int. Cl. ..H0lh1/54 [58] Field of Search ..335/205, 206, 207, 285; ZOO/61.62, 61.73,61.84; 340/274 [56] Relerences Cited UNITED STATES PATENTS 2,289,0277/1942 Lyle ..200/6l.62 X 2,526,206 10/1950 Dolan ..340/274 Voland..'.....335/207 X Primary ExaminerBemard A. Gilheany AssistantExaminer-R. NQ Envall, Jr. Attorney-Polachek, Saulsbury & Hough [57]ABSTRACT A conductive permanent magnet structure fixed on the frame of aprotected opening, attracts into contact with itself, a conductiveloosely slidable armature having limited movement on the closure member;such magnet and slide constituting a switch protecting the opening. inclosed condition of the switch, these switch parts are contiguousportions of the current path in the protective circuit. In installationswhere slide movement during the attraction is vertical, gravity returnsthe slide to a rest position, to be ready for a reestablishment of theprotective circuit. When such direction is horizontal, the slide isautomatically cammed to be in proper position if necessary, for theprotective circuit to be put into operative condition. These switchesavoid the need of cords across a parting of the frame and its closure.Stocking a few parts, affords the fabrication of switches of differentconstructions, either in the shop 7 or on the job, to meet installationrequirements and conditions.

7 Claims, 14 Drawing Figures SPRINGLESS SWITCH CONSTRUCTIONS FOR USE INTIIE PROTECTIVE CIRCUIT OF BURGLAR ALARM SYSTEMS .essential combinationthat one part thereof is a permanent magnet structure, and itsother partis the armature, forming contiguous portions of the current path whensuch switch is closed, or such switches may comprise variouscombinations of magnets and armatures forming current path when suchcircuit is in closed condition.

As is well known in burglar alarm systems generally, they giveprotection by actuating the alarm circuit when there is an unauthorizedmovement .of the closure member of a protected opening, from closingposition, and when there is a breakage of conductive tape mounted onglass pane structure. It is preferred in the practice of this inventionthat the armature shall be movably mounted on the closure member, andthat its companion magnet structure shall be fixedly carried on theframe member oftlre protected opening. Upon bringing the closure memberto closing position, the armature is attracted by its related magnet tobe in contact therewith, thus offering path for current in theprotective circuit. Upon movement of the closure member to an openposition, the armature returns to a rest position on the closure member,automatically in prior switches of this class, because the armatureswere springbiased. Such construction involved expenses in material andlabor which added appreciably to the cost of manufacture.

It is therefore an object of this invention to provide a novel andimproved magnetic switch construction of the character described, whichis springless. Its simplified makeup, lowers its cost, and yet, there istimely return of the armature accomplished automatically, regardless ofwhether the armature movement need be vertical or horizontal, to beproperly oriented.

The preferred form of the armature in thepractice of this invention,'isthat it shall be a slide on the closure member with a limited scope ofmovement determined by what it has to do when the closure member it ison, assumes closed position, and then when said member is shifted toopen position. The slide has some special construction as willbedescribed. Where the frame and closure are of woodenconstructiom-theswitch parts, though they carry current, may be mounted thereondirectly, as is evident. If the mounting surfaces are of conductivematerial, for they are of metal in modern buildings, the said switchparts need be mounted so they are insulated from the building and fromeach other.

It is therefore another object of this invention to provide insulativemounts for the switch parts which will also serve as tracks for theslides, and which will present the magnets for action on the slideswhich are the armatures as mentioned.

A further object thereof is to have the magnets and armatures as well asthe insulative mounts therefor, marketed as separate pieces, so with asupply of them as stock, the electrician can readily fabricate anycombination of them to suit the different conditions and installationshe need make for any alarm system to meet switch requirements. I

A further object of this invention is to provide novel and improvedmagnetic switch constructions of the kind set forth, having the statedattributes and advantages, and which are simple, easy to install andefficient in carrying out the purposes for which they are designedinvolving new modes of operation brought about by novel cooperation ofthe parts.

Other objects and benefits of this invention will become evident as thisdisclosure proceeds. For example, these 7 switches make it unnecessaryto have permanent cords across a parting between a closure and theframe.

For one practice of this invention, one part of the switch is apermanent magnet mounted fixed on the frame of a protected opening, andthe other part is a loose armature which is a slide on the closuremember of said opening, so arranged that when the closure member is inclosing position, the armature is attracted by the magnet into contacttherewith, so the switch such parts constitute, is in closed condition;such parts offering contiguous portions of the current path in theprotective circuit of the burglar alarm system. No springs are used tobring the slide to any position. Where armature movement is upwardlyvertical when attracted by the magnet, the move-. ment of the closuremember to open position,.will allow gravity to act on the raised slide,to accomplish automatic returnto its rest position on the closuremember; the limits of movement permitted the slide allowing it tocome.to the magnet when subject thereto, with an impact on contact. Wherearmature movement is downwardly when attracted by the magnet, thearmature on contact therewith will retract a bit from its loweredposition and make good contact with the magnet.

When the installation is such that armature movement is along thehorizontal when attracted by the magnet, should the armature beaccidentally in a position to be intercepted by the magnet or otherstructure, so the closure member could not complete its required travel,then cam means on the slide, will automatically shift the slide to aretracted position, thereby allowing completion of the necessarymovement of the closure I member. When the building structure is ofmetal, insulative backings or mounts are included. Various combinationsand arrangements are made of these magnets and slide armatures, to suitthe needs of particular installations. These switch parts and insulativepieces can constitute stock parts for fabricacuit will be actuated. Thewindow isshown in closed condition.

FIG; 2 is a view like FIG. 1, with the window open.

. FIG. 3 is an enlarged fragmentary section taken at line 3-3 in FIG. 1;

FIG. 4 is a perspective view showing the switch parts of the kind usedfor the switch structure included in FIG. 1.

FIG.- 5 is a fragmentary front view of a window equipped with anotherarrangement of switch structure of slightly modified construction, whichwill cause the actuation of the alarm circuit when the window is open.The wiring diagram of the burglar alarm system is fragmentarily shown.

' FIG. 6 is a view like FIG. 5, with the window open.

FIG. 7 is a perspective view showing the switch parts included in theinstallation shown in FIG. 5.

FIG. 8 is a perspective view of an insulating piece for. use to mountthe magnet structure on, where the window frame is of metal.

FIG. 9 is a perspective view of another slightly modified form of magnetstructure. The insulative piece of FIG. 8, is useable as a backingtherefor.

FIG. 10 is a perspective view showing an assembly of the two magnets ofFIG. 7, on an insulative piece.

FIG. 11 is a perspective view showing the insulative piece included inFIG. 10, in inverted position.

FIG. 12 is a top plan view of FIG. 10. Included fragmentarily, is theassociated armature on an insulated mount.

FIG. 13 shows in perspective, the parts of the insulative mount whichcarries the armature as included in FIG. 12.

FIG. 14 is a front view which is partly in section, showing the magnetstructure on its insulative mount, contacting the armature which isshown in assembly with its own insulative mount which comprisesjtheparts shown in FIG. 13.

In FIGS. 1 and 2, the means for mounting and slidably guiding the slidearmature, is symbolized by a line S," and in FIGS. 5 and 6, by a line8'.

A detailed description will now be given.

In the drawing, the numeral 20 designates generally a conductivepermanent magnet structure, and the numeral 21 indicates generally theconductive armature therefor. These basically, are the parts of switchesto be made for use in theprotective circuit 22 of burglar alarm systemsso upon a violation of a protected opening, the alarm circuit 23 shallbe actuated. As shown, it is preferred that the structure comprise ablock 24 which is a barium ferrite flexible magnet or the magnetmaterial marketed under the name of "Alnico, set within a channel 25 ofsheet steel, through which block and channel are aligned holes centrallylocated as 26, for the reception of a wood screw, when such magnetstructures are to be mounted on woodwork as in FIGS. 1 and 5. Of course,any permanent magnet may be used in its stead, without the channel. Thearmature 21, in all instances shown, is a slide made of sheet metal, andpreferably isof the form illustrated, which comprises a channel ofrectangular shape, whose floor wall has a crosswise slot 27 which isalong the direction of its sliding movement. The end edges of one of itssidewalls 28, has the outward wing extensions 29, 29' which divergetowards the other sidewall 28, and serve as cams as will be explained.Two wood screws 30,30 mount the armature on the woodwork, and theirspacing will of course determine the scope of movement of the slide. Thenumeral 31. indicates a threaded hole for a binding post screw 32, towhich connection may be made by having the connecting wire first passthrough the hole 31 Similar provision may be made by holes in thechannel wall 28. If desired, the channel may have a mounting lug 33integral therewith in any desired direction which may be other thanshown, and such lug may be used for a-binding post screw 34 asillustrated in the embodiment FIG. 12, designated as 20, and there maybe two lugs as in the magnet structure 20".

In FIG. 1, the numeral 35 designates generally a window having a woodenframe 36, a lower sash 37, and an upper sash 38, both these sasheshaving wood frames for their glass panes 39 and 40 respectively, each ofwhich has an open loop as 41 of metallic tape adhered thereto in amarginal format, as is well known in the burglar alarm art, to be partof the closed protective circuit 22, so should a pane be broken, itstape will also break, and hence the alarm circuit 23 would be actuated.Tow permanent magnet structures 20 are mounted in spaced relation on thebottom surface of the overhang of the window frames upper rail 42-. Foreach magnet, there is an armature 21' which is slidably mounted on theface of the upper slat 43 of the upper sash 38, in similar spacedrelation so that each armature is directly opposite its respectivemagnet, and slidably mounted for movement along the vertical, will beattracted with impact into contact with its companion magnet when theupper sash is raised to closed position. The installation of saidslidable armatures and the location of the mounting screws 30,30therefor respectively, shall allow the armatures to override, so contactcaused by magnetic attraction shall be with an impact 'to effect goodcontact. The extent of permitted return downward movement of thearmatures shall keep them within the influence of the magnets, when theupper sash is raised. The wings 29,29 serve as weight to aid the actionof gravity to return the slide armatures to their normal lowered restpositions on the sash. Conductors 44,44 leading from said magnets, areinterposed as switch terminals in the protective circuit; the tape 41being connected to shunt the magnets, by having its ends connected tothe respective binding posts 32 by short pieces of flexible wire 45,45,whose ends and those of the tape loop are connected, and held supportedon an insulative piece 46 which is adhered to the pane 40.

The installation involving the lower sash 37 and the metallic tape 45 onits pane 39, will have the same switch installation and connections asfor the upper sash. Of course, the magnets will be mounted therefor onthe window sill, and their armatures will be on the lower rail of thelower sash, all of which is believed readily understood by those versedin the art, so no further showing or explanation is necessary. When thewindow 35 is closed top and bottom, and the burglar alarm system is setinto operative condition, as is well known, upon the movement of any ofthe sashes to an open position, or should any of the tapes 41 or 45 bebroken, the protective circuit 22 will become open, and cause actuationof the alarm circuit 23.

It is evident that if the protection sought is only against the openingof the window, meaning that the tapes 41 and 45 are omitted, then, thepair of armatures would be connected by a conductor on each sashrespectively, or the two magnets for each sash, would need only onearmature to shunt both of them, as shown in another installation in FIG.5, all of which is believed readily comprehended without the need of anyfurther illustration.

In the installation of protective switch means shown in FIG. 5, thepermanent magnets 20' are mounted slightly spaced along the vertical onthe inner face of the vertical section 46 of the window frame 47, andhave the single armature 21' which is slidably mounted for horizontalmovement on the vertical frame piece 48 of the lower sash 49 of thewindow 50, and so arranged that when the said s'ash is down, saidarmature will overlap and contact both said magnets and shunt them;conductors 51 and 52 respectively connected to said magnets, areinterposed as the switch terminals of such installation, in theprotective circuit, wherein all switches are in series as is well known.It is important to note that here, it is the cam-carrying wall 28 of thearmature, that makes contact with the magnets 20', and is moved theretoupon lowering of the sash to closed position. When the premises areoccupied and the alarm system is set into inoperative condition, thesash may be raised to keep the window open. Raising the sash 49, will ofcourse carry the armature 21' with it, which will remain in brush wipingcontact of the upper magnet until it passes it as shown in FIG. 6. Ifthere has occurred no accidental displacement of the armature so that itlies in the path of the upper magnet, subsequent lowering of the sash49, will not affect reestablishment of the shunt. In particular, it isto be noted that even if such displacement did happen, the interceptionof the armature by the uppermost edge of the magnet structure will notprevent full downward movement of the sash, because the wing 29', comingin contact with said edge, will act as a cam upon further downwardmovement of the sash, and cause the armature 21 to move to the right,sufficient to allow sash movement and so contact of the armature withboth magnets can be established. Magnetic attraction does its work, andwhen armature displacement is towards the right, there certainly is nointerference with switch function. For the protection of the upper sash53, a similar switch installation is provided therefor, the includedarmature of which would be on the sash frame piece 54. This is fullyunderstandable without further illustration, as well as the use of thedouble armature switch means and the inclusion of a tape loop, where themagnets would be as in FIG. 5, at the side of the window, but using thearrangement of switch structure as in FIG. 1.

Where window frame and sash construction is of metal, it is of coursenecessary to have the switch parts insulated therefrom. For mounting themagnets, a plastic T-shaped underlay 55 may be used, which has the holes56,56 for screws for attachment to the building structure. The threadedhole 57 is for a short screw to hold the magnet structure, and the holes58,58 are clearance holes for terminal connection screws, as forinstance in the hole 33 which may be threaded so it can receive suchscrew; all screws through the holes 57,58 and 58' ending within the bodyof the insulating backing piece 55. A suitable insulator for one of themagnets may be just part of said piece 55, that is, it may be an L-shapemade by omitting one of the horizontal perforated extensions 59. On oneface, it would be for a right lugged, and on its other face, it would befor a left lugged channel component when the magnets are as shown inFIG. 7. The T-fonn scheme is included in the insulator constructionshown in FIG. 11, which is for mounting a pair of magnets, which may beused for the switch arrangements of FIGS. 1 and 5, and particularly, forFIG. 5, the feet 61,61 may be included to cooperate with the camextension pieces 29 and 29 as is illustrated in FIG. 12.

A dielectric mount for the slidable armature 21, is illustrated in FIGS.13 and 14, where the backing member 62, moulded of plastic, iscross-shaped, with holes 63 for mounting screws on a line crossing anintegral elongated boss 64 which is received as a track means in andalong the slot 27 of the armature, out of which it extends a bit toallow the annature its sliding movement. The assembly is maintained by apiece or tab 65 which overlaps the edges of said slot and is cementedonto the boss 64.'The length of said boss is less than the length of thesaid slot, a distance which determines the extent of slide travel. 1 I

The permanent magnet-used in these switch means is a conductive block,whose use this invention includes, the armature is arranged to contactone of its poles which might be its large faces. Where the magnetstructure is .built up as illustrated, using the steel channel filled bya magnetic block which might be nonconductive, armature contact is madewith the face, or with one or both longitudinal edges, of the channelwalls. The assembly shown in FIG. 10, whether mounted on a wall orsurface, resting either on the plate 66 or the feet 61,61, any of thechannel walls and their longitudinal edges, are accessible for choice tobe contacted by the armature.

For installation of required switch arrangements, they may be fabricatedon the job, or prefabricated in the shop, from a stock in hand of themagnet structures and the armature, shown in the FIGS. 4, 7'and 9, andof insulator elements, as for instance shown in the FIGS/8, 11 and 13,and of course a supply of mounting screws and those to make connectionsto conductors to be interposed in the circuit.

This invention is capable of numerous forms and various applicationswithout departing from the essential features herein disclosed. It istherefore intended and desired that the embodiments herein shall bedeemed merely illustrative and not restrictive and that the patent shallcover all patentable novelty herein set forth; reference being had tothe following claims rather than to the specific showing and descriptionherein, to

v permanent magnet structure and the other of which is an armature forsaid one part; one of said switch parts being fixedly mountable on oneof said members and means for loosely slidably mounting the other switchpart on the other of said part when the closure member is in closingposition, holding said slidable switch part at a position that it willbe attracted by the magnetic action into contact with the fixed switchpart, when the closure member assumes closed position; the other stopallowing the slidable switch part a greater distance of travel towardsthe fixed switch part than is necessary for it to reach the fixed switchpart when the closure member assumes closed position whereby on movementinto contact with the fixed switch part, the movable switch part willmeet it with an impact. I g

3. A switch device as defined in claim 2, wherein the magnet is fixed onthe frame member, and the armature is loosely slidably mounted on theclosure member.

4. A switch device as defined in claim 3, including a dielectric backingpositioned fixed on the closure member and carrying the slide switchpart; said backing being between the slide and closure member; saidslide having an elongated slot along the direction it need move, a bossof insulative material extending fixed from said backing and intosaidslot to serve as a track for said slide; said boss being shorter thanthe length of said slot a distance equal to the scope 'of movement ofthe slide, and means attached to the longitudinal exposed face of the,boss, overlapping the longitudinal edges of said slot, to maintain theassembly; the slide being loose for free movement on said backing. I

5. A switch device as defined in claim 1, wherein the line of movementof the closure member is along the vertical, and the line of movement ofthe slide switch part on the closure member is also along the vertical;the direction of movement of the closure member to closing positionbeing the same as the direction of movement of the slide switch part onthe closure member when it moves into contact with the other switch partby the action of magnetic attraction.

6. A switch device as defined in claim 1, wherein the line of movementof the closure member is along the vertical and the line of movement ofthe slide switch part is along the horizonmembers and said other switchpart being shiftable into contact with the first switch part when theclosure member is in a closed position, such that said switch partsremain in contact by action of magnetic attraction of one of said partsfor the other of said parts; said switch parts being separated upon thetal; the slide switch part being on the closure member, and including acam element extending from the slide switch part to that edge of thefixed switch part that the movable slide switchpart approaches when theclosure member is moving from fully open position to fully closedposition, whereby when the slide switch part is accidentally in positionso that its cam is intercepted by said edge when the closure member ismoving from open to closed position, said cam in cooperation with saidedge will cause the slide switch part to shift and clear the fixedswitch part thereby allowing the closure member to proceed to closedposition.

7. A switch device as defined in claim 6, including a dielectric backingon the frame and carrying the fixed switch part, an insulative tab onsaid backing presenting the first edge the cam would meet when theclosure member is moving to fully closed position; said edge of the tabcooperating with the cam for moving the slide switch member to allow theclosure member to proceed to fully closed position.

1. In a springless switch device interposed in a conductor included inthe circuit of an electrical burglar alarm system protecting a framemember having a movable closure member; said switch comprising twoconductive parts one of which is a permanent magnet structure and theother of which is an armature for said one part; one of said switchparts being fixedly mountable on one of said members and means forloosely slidably mounting the other switch part on the other of saidmembers and said other switch part being shiftable into contact with thefirst switch part when the closure member is in a closed position, suchthat said switch parts remain in contact by action of magneticattraction of one of said parts for the other of said parts; said switchparts being separated upon the closure member assuming an open position;said switch parts when in contact being formable of contiguous portionsof the current path through said conductor.
 2. A switch device asdefined in claim 1, including stops associated with that member theslidable switch part is on, and with said slidable switch part,determining the scope of movement of said slidable part on the member itis on; such part when at one such stop which is farthest from the fixedswitch part when the closure member is in closing position, holding saidslidable switch part at a position that it will be attracted by themagnetic action into contact with the fixed switch part, when theclosure member assumes closed position; the other stop allowing theslidable switch part a greater distance of travel towards the fixedswitch part than is necessary for it to reach the fixed switch part whenthe closure member assumes closed position whereby on movement intocontact with the fixed switch part, the movable switch part will meet itwith an impact.
 3. A switch device as defined in claim 2, wherein themagnet is fixed on the frame member, and the armature is looselyslidably mounted on the closure member.
 4. A switch device as defined inclaim 3, including a dielectric backing positioned fixed on the closuremember and carrying the slide switch part; said backing being betweenthe slide and closure member; said slide having an elongated slot alongthe direction it need move, a boss of insulative material extendingfixed from said backing and into said slot to serve as a track for saidslide; said boss being shorter than the length of said slot a distanceequal to the scope of movement of the slide, and means attached to thelongitudinal exposed face of the boss, overlapping the longitudinaledges of said slot, to maintain the assembly; the slide being loose forfree movement on said backing.
 5. A switch device as defined in claim 1,wherein the line of movement of the closure member is along thevertical, and the line of movement of the slide switch part on theclosure member is also along the vertical; the direction of movement ofthe closure member to closing position being the same as the directionof movement of the slide switch part on the closure member when it movesinto contact with the other switch part by the action of magneticattraction.
 6. A switch device as defined in claim 1, wherein the lineof movement of the closure member is along the veRtical and the line ofmovement of the slide switch part is along the horizontal; the slideswitch part being on the closure member, and including a cam elementextending from the slide switch part to that edge of the fixed switchpart that the movable slide switch part approaches when the closuremember is moving from fully open position to fully closed position,whereby when the slide switch part is accidentally in position so thatits cam is intercepted by said edge when the closure member is movingfrom open to closed position, said cam in cooperation with said edgewill cause the slide switch part to shift and clear the fixed switchpart thereby allowing the closure member to proceed to closed position.7. A switch device as defined in claim 6, including a dielectric backingon the frame and carrying the fixed switch part, an insulative tab onsaid backing presenting the first edge the cam would meet when theclosure member is moving to fully closed position; said edge of the tabcooperating with the cam for moving the slide switch member to allow theclosure member to proceed to fully closed position.